What is molarity?

Molarity is defined as a measure of concentration in chemistry, specifically the concentration of a solute in a solution. It is mathematically expressed as the number of moles of that solute divided by the volume of the solution in liters. This relationship makes it a crucial concept for understanding how substances interact in solutions, as it allows chemists to predict how reactions will occur based on the concentration of reactants.

For example, if you have a solution with 1 mole of salt dissolved in 1 liter of water, the molarity of that solution would be 1 M (1 mol/L). This concept helps in preparing solutions of desired concentrations for various chemical reactions and experiments. Understanding molarity is fundamental in areas such as stoichiometry, where it aids in calculating how much solute is needed for reactions or how much product can be formed.

In contrast, other options do not accurately describe molarity. For instance, the volume of a solution and measurement of pressure pertain to different aspects of chemistry, while quantifying the mass of a solid relates to mass measurements rather than concentration. Thus, option C clearly captures the specific and essential definition of molarity in the context of solution chemistry.